Related papers: A proposal for climate stability on H2-greenhouse …
Quantifying disequilibria is important to understand whether an environment could be habitable. It has been proposed that the exoplanet K2-18b has a hydrogen-rich atmosphere and a water ocean, making it a "hycean world". The James Webb…
Habitable rocky planets around M dwarfs that have H2-dominated atmospheres, if they exist, would permit characterizing habitable exoplanets with detailed spectroscopy using JWST, owing to their extended atmospheres and small stars. However,…
Conventionally, a habitable planet is one that can support liquid water on its surface. Habitability depends on temperature, which is set by insolation and the greenhouse effect, due mainly to CO2 and water vapor. The CO2 level is increased…
Determining planetary habitability is a complex matter, as the interplay between a planet's physical and atmospheric properties with stellar insolation has to be studied in a self consistent manner. Standardized atmospheric models for…
According to the standard liquid-water definition, the Earth is only partially habitable. We reconsider planetary habitability in the framework of energy-balance models, the simplest seasonal models in physical climatology, to assess the…
A consistent finding of high obliquity simulations is that they are warmer than their low obliquity counterparts when the climate is cold. Ice-albedo feedback has been suggested as a possible mechanism. In this study, we find that warmer…
Ongoing and future space missions aim to identify potentially habitable planets in our Solar System and beyond. Planetary habitability is determined not only by a planet's current stellar insolation and atmospheric properties, but also by…
Planets similar to Earth - but slightly more irradiated - are expected to enter into a runaway greenhouse state, where all surface water rapidly evaporates, forming an optically thick H2O-dominated atmosphere. For Earth, this extreme…
The nearly logarithmic radiative impact of CO$_2$ means that planets near the outer edge of the liquid water habitable zone (HZ) require $\sim$10$^6$x more CO$_2$ to maintain temperatures conducive to standing liquid water on the planetary…
Hycean planets -- exoplanets with substantial water ice layers, deep surface oceans, and hydrogen-rich atmospheres -- are thought to be favorable environments for life. Due to a relative paucity of atmospheric greenhouse gases, hycean…
Although non-greenhouse gases can vary substantially in abundance in Earth-like atmospheres, their climatic influences remain insufficiently understood. To investigate how such gases regulate climate, we vary the abundance of N$_2$ as a…
Traditional definitions of the habitable zone assume that habitable planets contain a carbonate-silicate cycle that regulates CO2 between the atmosphere, surface, and the interior. Such theories have been used to cast doubt on the…
Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study…
Global climate evolution models for habitable earthlike planets do not consider the effect of ocean salinity on land ice formation through the hydrological cycle. We consider two categories of such planets: planets with deep oceans, but…
Exoplanet habitability is traditionally assessed by comparing a planet's semi-major axis to the location of its host star's "habitable zone," the shell around a star for which Earth-like planets can possess liquid surface water. The Kepler…
The tidal heating of hypothetical rocky (or terrestrial) extra-solar planets spans a wide range of values depending on stellar masses and initial orbits. Tidal heating may be sufficiently large (in many cases, in excess of radiogenic…
A planet's climate can be strongly affected by its orbital eccentricity and obliquity. Here we use a 1-dimensional energy balance model modified to include a simple runaway greenhouse (RGH) parameterization to explore the effects of these…
Habitability is a measure of an environment's potential to support life, and a habitable exoplanet supports liquid water on its surface. However, a planet's success in maintaining liquid water on its surface is the end result of a complex…
Planetary rotation rate is a key parameter in determining atmospheric circulation and hence the spatial pattern of clouds. Since clouds can exert a dominant control on planetary radiation balance, rotation rate could be critical for…
There are four different stable climate states for pure water atmospheres, as might exist on so-called "waterworlds". I map these as a function of solar constant for planets ranging in size from Mars size to 10 Earth-mass. The states are:…